In a known monolithically integrated semiconductor, Darlington transistor circuit, disclosed in DE-OS 32 37 536, FLOHRS/BOSCH and corresponding WO 83-02528, publ. Jul. 21, 1983, a substrate under a first main surface is weakly doped (substrate region n.sup.-) and under another main surface, at least of the finished arrangement, is strongly doped with the same type of conductivity (substrate region n.sup.+). A first zone (p), which forms a pn-junction with the substrate, and a second zone (n.sup.+) of the same conductivity type as the substrate but which does not touch the first zone (p), are diffused in from the main surface.
The first main surface of the substrate is covered by an insulating passivation layer, with the exception of contact windows. A metallic cover electrode is located above this layer, which covers the substrate areas (substrate region n.sup.-) bordering the first main surface, the edge areas of the first zone (p) and the edge areas of the second zone (n.sup.+).
By means of the metallic cover electrode located above the space-charge limited current region, protection of a planar transistor arrangement against environmental influences, possibly connected with an effect on the break-through voltage, is achieved here. For this purpose, the cover electrode is connected to a potential between base and collector determined by a voltage divider. The break-through voltage is essentially determined by this potential and the thickness of the oxide under the cover electrode.
Employment of a voltage divider is a relatively expensive step, its integration into the semiconductor arrangement requiring silicon surface. In addition, it is desirable to achieve a higher break-through voltage with the same oxide thickness.